JP2021098464A - Shock absorbing structure - Google Patents

Abstract

To provide a shock absorbing structure for a vehicle interior material which has a simple configuration and excellent shock absorbing performance.SOLUTION: There is provided a shock absorbing structure for a vehicle interior material 20. The vehicle interior material 20 includes: a plate-like substrate 23 including a fiber 21A and a foamable resin 21B; and a plate thickness part 25 made of the foamable resin 21B and provided integrally with the substrate 23 of which partial thickness dimension becomes large as compared to the periphery in the substrate 23. A shock absorbing member 30 is disposed on an exterior side of the plate thickness part 25 while being installed separately from the substrate 23.SELECTED DRAWING: Figure 2

Description

The techniques disclosed herein relate to shock absorbing structures in vehicle interior materials.

Patent Document 1 below discloses a door trim based on a hard or semi-rigid polyurethane foam, in which a cushioning material made of polyurethane foam is integrally molded with the base material at a desired portion of the door trim. There is.

Japanese Unexamined Patent Publication No. 6-191278

However, in the shock absorbing structure disclosed in Patent Document 1, it is necessary to increase the thickness of the cushioning material by the polyurethane foam in order to increase the required energy absorption amount, which may be a factor of reducing the indoor space.

In order to realize the desired shock absorption performance without increasing the size of the shock absorption structure, for example, the shock absorption structure is composed of two parts having different hardness, and the shock energy absorption mode in the shock absorption structure is appropriately designed. Is also possible. However, in such a complicated configuration, there is a concern that the number of parts related to the shock absorbing structure will increase and the cost will increase.

The technique disclosed in the present specification has been completed based on the above circumstances, and an object thereof is to provide a shock absorbing structure in a vehicle interior material having a simple structure and excellent shock absorbing performance. To do.

In order to solve the above problems, the shock absorbing structure disclosed in the present specification is a shock absorbing structure in a vehicle interior material, and the vehicle interior material is a plate-shaped base containing fibers and a foamable resin. The plate includes a material and a plate thickness portion made of the foamable resin, which is integrally provided with the base material so that a part of the thickness dimension of the base material is larger than the surrounding area. A shock absorbing member provided separately from the base material is arranged on the outdoor side of the thick portion.

According to such a shock absorbing structure, the shock energy at the time of a vehicle side collision can be absorbed not only by the shock absorbing member but also by the thick portion. Since such a plate thickness portion is integrally provided with the base material by the foamable resin constituting the base material, it is not necessary to separately provide a structure made of the foamable resin corresponding to the plate thickness portion, and also. It is not necessary to attach a separately provided structure made of foamable resin to the door trim. Therefore, it is possible to provide a shock absorbing structure having excellent shock absorbing performance with a simple configuration.

The shock absorbing member may be a resin molded body having ribs extending along the indoor and outdoor directions. According to such a configuration, the shock absorbing member has the shock absorbing property due to the buckling deformation of the rib, and the plate thickness portion has the shock absorbing property due to the deformation of the foamable resin. Early restraint of the occupants can be realized, and the amount of energy absorption can be appropriately controlled by the plate thickness portion. Therefore, the shock absorption performance of the shock absorption structure can be improved.

The shock absorbing member further includes a contact wall portion that extends along the outdoor surface of the plate thickness portion and is arranged so as to abut the outdoor surface, and the ribs abut. It may be erected on the wall. According to such a configuration, the contact wall portion abuts on the outdoor surface of the plate thickness portion, so that the load input to the rib of the shock absorbing member is applied to the plate thickness portion via the contact wall portion. It becomes easy to input uniformly to the outdoor surface. Therefore, the impact energy can be suitably absorbed by the thick portion.

According to the technique disclosed in the present specification, it is possible to provide a shock absorbing structure in a vehicle interior material having excellent shock absorbing performance with a simple configuration.

Front view of the door trim according to the first embodiment Cross-sectional view of the vehicle door (corresponding to the view cut along line II-II in FIG. 1) Explanatory drawing explaining the formation mode of a base material and a plate thickness part Graph showing load / displacement characteristics Cross-sectional view of the vehicle door according to the second embodiment

<Embodiment 1>
The first embodiment will be described with reference to FIGS. 1 to 4. In the present embodiment, the shock absorbing structure 40 in the door trim (vehicle interior material) 20 arranged on the interior side of the vehicle panel 11 and forming the vehicle interior surface of the vehicle door 10 will be illustrated.

The vehicle panel 11 is composed of an inner panel 11A and an outer panel 11B, and is formed by, for example, pressing a metal plate material such as iron or aluminum and combining the metal plate materials. The inner panel 11A is arranged so as to face the indoor side of the outer panel 11B. Functional parts such as a window regulator (not shown) for raising and lowering the window glass 14 and a lock mechanism (not shown) for locking the vehicle door 10 are arranged between the inner panel 11A and the outer panel 11B. ing. A service hole 11C for assembling and maintaining these functional parts is formed on the inner panel 11A, and a service hole cover 12 is attached to the service hole 11C.

As shown in FIG. 1, the door trim 20 is mainly composed of the trim board 21. The indoor surface of the trim board 21 is covered with a skin material (not shown). Further, the door trim 20 is provided with various functional parts such as an armrest portion 16 extending in the front-rear direction of the vehicle, an inside handle 17, a speaker grill 18, and a door pocket 19.

As shown in FIG. 2, the trim board 21 has a plate-shaped base material 23 containing the fibers 21A and the foamable resin 21B, and a part of the base material 23 has a thickness dimension larger than that of the surroundings. It is provided with a plate thickness portion 25 made of a foamable resin 21B, which is integrally provided with the base material 23. The base material 23 is a fiber composite material in which fibers 21A are bonded to each other by a foamable resin 21B, and has a lightweight and highly rigid structure.

As the fiber 21A, for example, a vegetable fiber collected from kenaf, cotton, hemp, sisal, jute or the like, an inorganic fiber such as glass fiber or carbon fiber, a fiber selected from synthetic resin fibers and the like can be used. Of these, a mallow plant that has kenaf, is an extremely fast-growing annual plant, has excellent carbon dioxide absorption, and contributes to the reduction of the amount of carbon dioxide in the atmosphere and the effective use of forest resources. It is particularly preferable that it is a linear fiber body (kenaf fiber) derived from kenaf.

As the foamable resin 21B, for example, hard or semi-hard polyurethane foam, polypropylene foam and the like can be used. Of these, a rigid polyurethane resin that is lightweight, has relatively high rigidity, and has a large impact energy absorption amount can be preferably used.

Further, the base material 23 produced from the rigid polyurethane foam in the present invention is particularly preferably satisfied with all of the following conditions from the viewpoint of satisfying the strength, light weight and dimensional stability required as the base material. That is,
A) The free foaming density of polyurethane foam is 45-150 kg / m ³ ,
B) The apparent density of the fibers is 0.02-0.25 g / cm ³ ,
C) The fiber content in the base material is 33% by weight to 75% by weight.
D) The average density of the base material is 0.15 to 0.5 g / cm ³ ,
E) The coefficient of linear expansion measured in the temperature range of -20 ° C to 20 ° C of the base material is 18 × 10 ^-6 / K or less.

Next, the shock absorbing structure 40 of the door trim 20 will be described with reference to FIG. In the shock absorbing structure 40, a shock absorbing member 30 provided separately from the base material 23 is arranged on the outdoor side of the plate thickness portion 25. In other words, the shock absorbing structure 40 is harder than the plate thickness portion 25 (first portion) made of the foamable resin 21B located relatively on the indoor side and the plate thickness portion 25 located relatively on the outdoor side. It has a structure composed of two parts having different hardness, including a shock absorbing member 30 (second part) made of resin. The shock absorbing structure 40 is arranged in the vicinity of the waist of the occupant seated on the seat (not shown) arranged on the indoor side of the door trim 20, and absorbs the shock energy at the time of a vehicle side collision, thereby forming the seat. It is intended to reduce the impact on the seated occupant (see FIG. 1).

The plate thickness portion 25 is made of a block-shaped or board-shaped foamable resin 21B as a whole, and is formed so as to project from the outdoor surface of the base material 23. The plate thickness portion 25 is a pressure receiving surface on which the outdoor surface 25A comes into contact with the shock absorbing member 30 and receives impact energy. The thickness dimension (protruding dimension) of the plate thickness portion 25 and its arrangement range can be appropriately set in consideration of the impact absorption performance of the impact absorption structure 40, but in the present embodiment, the plate thickness portion 25 is impacted. In a form that complements the shock absorbing performance of the absorbing member 30, the shock absorbing member 30 is provided in a range smaller than the indoor / outdoor dimension of the shock absorbing member 30 and substantially the same as the arrangement range of the shock absorbing member 30.

The plate thickness portion 25 is formed of the foamable resin 21B material which is formed together with the base material 23 and impregnated with the fibers 21A. The method for forming the plate thickness portion 25 together with the base material 23 is not particularly limited, but for example, a plate is formed on a molding die 29 for press-molding the base material 23 from a mat-shaped kenaf fiber and a polyurethane resin material. It can be formed by forming a cavity 29A for forming the thick portion 25 and foaming a polyurethane resin material in the cavity 29A (see FIG. 3).

The shock absorbing member 30 has a substantially box shape that opens toward the outdoor side as a whole, and is made of a non-foamable thermoplastic resin such as polypropylene resin that is harder than the plate thickness portion 25. The shock absorbing member 30 extends along the outdoor surface 25A of the plate thickness portion 25 and stands on the contact wall portion 31 arranged so as to abut the outdoor surface 25A and the contact wall portion 31. It is a resin molded body including ribs 33 having a shape extending along the indoor and outdoor directions provided.

The contact wall portion 31 has a flat plate shape that covers the plate thickness portion 25. In addition, "the contact wall portion 31 is arranged so as to abut on the outdoor surface 25A (of the plate thickness portion 25)" means that the contact wall portion 31 is always on the outdoor side of the plate thickness portion 25. It is assumed that not only the configuration of contacting the surface 25A but also the configuration of being in a non-contact state at all times and the contact wall portion 31 contacting the outdoor surface 25A of the plate thickness portion 25 at the time of a vehicle side collision is included. The contact wall portion 31 is provided with an attachment portion 35 for attaching the shock absorbing member 30 to the door trim 20 so as to extend from the peripheral edge portion thereof. Specifically, the mounting portion 35 has a mounting hole 35A, the door trim 20 is provided with a mounting boss 27 at a position corresponding to the mounting hole 35A, and the mounting boss 27 is inserted into the mounting hole 35A and ultrasonically crimped or the like. The shock absorbing member 30 is attached to the door trim 20.

The rib 33 includes a side wall portion 33A that rises from the peripheral end portion of the contact wall portion 31 toward the outdoor side, and a cross-shaped connecting wall portion 33B that connects the side wall portions 33A facing each other. Has been done. The height dimension of the rib 33 is set to be larger than that of the plate thickness portion 25, and the rib 33 is configured so that a displacement amount at the time of buckling can be obtained. The shock absorbing member 30 has a configuration in which a desired shock absorbing performance can be appropriately designed by appropriately designing the shape of the rib 33, the plate thickness, and the like.

Next, the shock absorption performance exhibited by the shock absorption structure 40 of the present embodiment will be described with reference to FIG. The graph shown by the solid line in FIG. 4 shows the load-displacement characteristics of the shock absorbing structure 40 of the present embodiment, and the graph shown by the alternate long and short dash line shows the shock absorption composed of only the shock absorbing member 30 of the present embodiment. It shows the load-displacement characteristics of the structure. Further, the horizontal axis in the figure indicates the amount of displacement in which the shock absorbing member 30 is pushed into the indoor side, and the vertical axis in the figure indicates the load received on the indoor side of the door trim 20.

The shock absorbing structure 40 of the present embodiment is shown in the range A in the figure by including, for example, a shock absorbing member 30 made of a hard resin molded body as compared with the shock absorbing structure made of only the foamable resin 21B. The initial load rises faster. Therefore, the lumbar region of the occupant can be restrained at an early stage, and the chest and abdomen can be protected. In addition, the amount of energy absorbed represented by the area on the lower side of the graph in the figure becomes large, and the impact energy is efficiently absorbed.

After that, in the range B in the figure, the impact energy is absorbed as the rib 33 of the impact absorbing member 30 buckles and deforms. In the range B in this figure, the load is kept substantially constant below the allowable upper limit load, and has ideal load-displacement characteristics in which impact energy is stably absorbed. When the buckling deformation amount of the rib 33 becomes small, as shown in the range C in the figure, the load gradually increases in the shock absorbing structure (graph shown by the dashed line) without the plate thickness portion 25. On the other hand, in the shock absorbing structure 40 (graph shown by the solid line) including the plate thickness portion 25, the impact energy is absorbed as the plate thickness portion 25 (foamable resin 21B) is deformed even in the range C in the figure, and for a while. The load increases after the load is kept substantially constant. At this time, since the shock absorbing member 30 is provided with the contact wall portion 31, the shock energy is input to the outdoor surface 25A of the plate thickness portion 25 substantially uniformly, and the shock energy is stably absorbed. Since the shock absorbing structure 40 includes both the plate thickness portion 25 and the shock absorbing member 30, the load is substantially constant in a wider range than the shock absorbing structure including only the shock absorbing member 30. Shows the load-displacement characteristics maintained at.

Subsequently, the effect of this embodiment will be described. According to the shock absorbing structure 40 in the door trim 20 of the present embodiment, the shock energy at the time of a vehicle side collision can be absorbed not only by the shock absorbing member 30 but also by the plate thickness portion 25. Since such a plate thickness portion 25 is integrally provided with the base material 23 by the foamable resin 21B constituting the base material 23, it is necessary to separately provide a structure made of the foamable resin corresponding to the plate thickness portion 25. Moreover, it is not necessary to attach a separately provided structure made of foamable resin to the door trim. In particular, when a structure made of polyurethane foam is attached to a door trim, it is difficult to bond the two with sufficient adhesive strength if the door trim has a structure containing polypropylene, which is widely used. Further, when a through hole is formed in a structure made of polyurethane foam and a mounting boss erected on a door trim is inserted through the through hole to mount the structure, the through hole is further provided in order to secure the mounting strength. It has a complicated structure such that a member for reinforcing the inner surface is separately required. On the other hand, in the present embodiment, since the base material 23 and the plate thickness portion 25 are integrally provided by the same foamable resin 21B, the door trim 20 in which the base material 23 and the plate thickness portion 25 are joined with sufficient strength can be obtained. Can be done. Therefore, it is possible to provide the door trim 20 having excellent shock absorbing performance with a simple configuration.

Further, in the present embodiment, the shock absorbing member 30 is a resin molded body provided with ribs 33 extending along the indoor and outdoor directions. Therefore, the shock absorbing member 30 has the shock absorbing property due to the buckling deformation of the rib 33, and the plate thickness portion 25 has the shock absorbing property due to the deformation of the foamable resin 21B. Early restraint of the occupants can be realized, and the amount of energy absorbed can be appropriately controlled by the plate thickness portion 25. Therefore, the shock absorption performance of the shock absorption structure 40 can be improved.

Further, in the present embodiment, the shock absorbing member 30 further extends a contact wall portion 31 which extends along the outdoor surface 25A of the plate thickness portion 25 and is arranged so as to abut the outdoor surface 25A. The rib 33 is erected on the contact wall portion 31. Therefore, when the contact wall portion 31 comes into contact with the outdoor surface 25A of the plate thickness portion 25, the load input to the rib 33 of the shock absorbing member 30 is applied to the plate thickness portion 31 via the contact wall portion 31. It becomes easy to input uniformly to the surface 25A on the outdoor side of 25. Therefore, a part of the plate thickness portion 25 is less likely to be locally deformed, and the impact energy can be suitably absorbed by the entire plate thickness portion 25.

<Embodiment 2>
Next, the second embodiment will be described with reference to FIG. In this embodiment, the shock absorbing structure 140 in which the mounting mode of the shock absorbing member is different from that of the first embodiment will be illustrated. It should be noted that duplicate description of the same structure, action and effect as in the above-described embodiment will be omitted.

The shock absorbing member 130 is integrally provided with a service hole cover 112 made of a non-foamable thermoplastic resin such as polypropylene resin, which is harder than the plate thickness portion 25. Then, by attaching the service hole cover 112 to the inner panel 11A, the shock absorbing member 130 is arranged on the outdoor side of the plate thickness portion 25. The structure of the rib 33 and the contact wall portion 31 in the shock absorbing member 130 is the same as that in the first embodiment, and the description thereof will be omitted.

In the present embodiment, the shock absorbing member 130 is provided integrally with the service hole cover 112, so that the configuration related to the shock absorbing structure 140 can be made even simpler.

<Other Embodiments>
The present invention is not limited to the embodiments described in the above description and drawings, and for example, the following embodiments are also included in the technical scope.
(1) In the above embodiment, the shock absorbing member is made of a resin molded body, but the present invention is not limited to this. For example, the shock absorbing member may be made of a foamable resin having a hardness different from that of the thick portion.
(2) In addition to the above embodiment, the shape and arrangement of the plate thickness portion and the shock absorbing member, and the assembling structure of each portion can be changed as appropriate. For example, the plate thickness portion may be provided in a range smaller than the arrangement range of the shock absorbing member so as to overlap only a part of the shock absorbing member. Further, the shock absorbing member is not limited to a configuration having ribs, and may have a concave-convex shape.
(3) In the above embodiment, the door trim is illustrated as the interior material for the vehicle, but the interior material for the vehicle may be an interior material for a vehicle other than the door trim such as a quarter trim, and a ship or an aircraft other than the vehicle. It may be an interior material equipped on a vehicle such as.
(4) The graph showing the load / displacement characteristics of the above embodiment is only an example, and the shock absorbing structure can be appropriately designed to exhibit the desired shock absorbing performance.

20 ... Door trim (interior material for vehicles), 21A ... Fiber, 21B ... Foamable resin, 23 ... Base material, 25 ... Plate thickness, 25A ... Outdoor surface, 30, 130 ... Shock absorbing member, 31 ... Contact Wall, 33 ... Ribs, 40, 140 ... Shock absorption structure

Claims (5)

It is a shock absorbing structure for interior materials for vehicles.
The interior material for vehicles is
A plate-shaped base material containing fibers and a foamable resin,
A plate thickness portion made of the foamable resin, which is provided integrally with the base material so that a part of the thickness dimension of the base material is larger than the surroundings, is provided.
A shock absorbing structure in which a shock absorbing member provided separately from the base material is arranged on the outdoor side of the thick portion. The shock absorbing structure according to claim 1, wherein the shock absorbing member is a resin molded body having ribs extending in the indoor and outdoor directions. The shock absorbing member further includes a contact wall portion that extends along the outdoor surface of the plate thickness portion and is arranged so as to abut the outdoor surface.
The shock absorbing structure according to claim 2, wherein the rib is erected on the contact wall portion. The shock absorbing structure according to any one of claims 1 to 3, wherein the foamable resin is a rigid polyurethane foam. The shock absorbing structure according to any one of claims 1 to 4, wherein the foamable resin is a rigid polyurethane foam and satisfies the following conditions.
A) The free foaming density of the rigid polyurethane foam is 45 to 150 kg / m ³
B) The apparent density of the fibers is 0.02-0.25 g / cm ³
C) The fiber content in the base material is 33% by weight to 75% by weight.
D) The average density of the base material is 0.15 to 0.5 g / cm ³
E) The coefficient of linear expansion measured in the temperature range of −20 ° C. to 20 ° C. of the base material is 18 × 10 ^-6 / K or less.

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